Appliances of the type referred to are known and typically constituted by cooking ovens or kitchen ranges comprising a cooking oven.
The above appliances comprise a metal load-bearing structure, which are associated with the muffle delimiting the cooking chamber and the corresponding front door. The muffle generally has an opening in its upper wall, on which a flue is mounted for expulsion of fumes from the cooking chamber. In certain solutions, extending above the upper wall of the muffle is a duct body—generally made of sheet metal—that defines a delivery channel, into which the flue gives out. The channel is shaped so as to present a corresponding outlet substantially at the front of the appliance, above an upper portion of the door. Some known ovens likewise comprise a ventilation assembly, operatively associated to a rear end of the duct body, so as to force the fumes along the delivery channel and expel them from its outlet, on the front of the appliance.
The fan used is typically a horizontal-axis tangential fan that, in certain known solutions, has a volute defining an air intake, for drawing in air into the structure of the appliance, generally from an area behind the rear wall of the muffle. In other known solutions, instead, the duct body also defines an intake channel, which extends underneath the delivery channel and has an inlet at the front of the appliance, substantially in a position corresponding to the upper portion of the door, underneath the outlet of the delivery channel The opposite end of the intake channel is located in a position corresponding to the tangential fan: in this way, relatively fresh air can also be drawn in from outside the structure of the appliance, in its front region, in order to mix said air with the fumes that exit from the cooking chamber and thereby enable a certain abatement of their temperature, prior to their expulsion at the front of the appliance.
The aforesaid arrangement including an intake channel and a delivery channel can also be used for inducing flows of cooling air into the door of the oven, in particular when the latter has functions of pyrolytic cleaning of the cooking chamber. In solutions of this type the flue is constituted by a generally vertical tubular body, fixed to the upper wall of the muffle at an opening thereof, with the upper end of said tubular body that projects into the intake channel, at an intermediate point of the latter between its front inlet and the tangential fan. In this way, the air taken in from the front of the appliance through the inlet of the intake channel can be mixed with the fumes coming from the flue, with the resulting mixture that is then expelled via the delivery channel, once again at the front of the appliance, above the upper portion of the door. The air drawn in from the front of the appliance through the intake channel is air conveniently present in one or more gaps of the front door of the appliance, which have respective openings in an area corresponding to the upper part of the door: in this way, a continuous air change is induced in the gaps, which enables reduction of the temperature of the door as a whole. For this purpose, at the upper portion of the door deflector elements are provided, configured for shielding the inlet of the intake channel and the upper openings of the gaps of the door with respect to the outlet of the delivery channel. An arrangement of this type is known for example from US 2004/159317 A1, on which the preamble of claim 1 is based.
Ovens of the above type, albeit on average efficient, present some drawbacks that it would be desirable to overcome.
One drawback of the known solutions regards the modalities of construction of the flue necessary for fluid connection of the cooking chamber to the delivery channel or intake channel of the duct body. The flue is formed by a tubular element relatively extensive in height, which must be mounted and fixed to the upper wall of the cooking chamber, at the outlet.
Another drawback is linked to the relatively distant positioning of the outlet or flue with respect to the tangential fan. In these conditions, the tangential fan is unable to generate high negative pressures in the flue, which must consequently have a rather large fume-outlet hole, with consequent dispersion of heat. This is also a consequence of the fact that the tangential fan is usually mounted in a position as retracted as possible on the upper wall of the muffle in order to also be able to draw in air from the area behind the muffle, whilst the flue must be preferably substantially located in a central area of the aforesaid upper wall in order to achieve its full effect.
A further consequence of the above known arrangement is that the duct body that defines the delivery channel, or the intake channel and the delivery channel, must extend practically from the rear area of the muffle substantially up to the front of the appliance. This arrangement, in addition to determining problems of encumbrance, implies a significant use of metal material in order to produce the duct body.
Further practical drawbacks derive from the need to couple, in the assembly step, the volute of the tangential fan, which is also usually made of metal material, to the duct body.
Other drawbacks are linked to a relatively low efficiency of the known systems in relation to the effect of cooling the inside structure of the oven and its door, in particular of the outermost part of the door, when this is provided with a number of gaps.